Power hammer



Jan. 30, 1968 E. F. BLICHARSKI POWER HAMMER 2 Sheets-Sheet 1 Filed Aug. 19, 1965 v Ja /em E. F. BLICHARSKI Jan. 30, 1968 POWER HAMMER Filed Aug. 19. 1965 2 Sheets-Shegt United States Patent 3,366,302 POWER HAMMER Edward F. Blicharski, 6015 Belmont Ave., Chicago, Ill. 60634 Filed Aug. 19, 1965, Ser. No. 480,909 13 Claims. (Cl. 227-131) ABSTRACT OF THE DISCLOSURE A power hammer having a head piece which is adjustable so as to move only a preset distance, as required for different work. An electric motor provides the driving and actuating force of the head piece. By positionably adjusting the head piece, a fine control is provided for, for example, driving and setting a nail or the like. A retractable nail guide which holds the hammer on a nail without slipping off is also provided.

This invention relates to power hammers and more particularly to power hammers "adapted to do the work normally done with conventional hammers, by using power to do the impact work quicker, better and easier.

Power hammers are generally known, however, those presently available are not intended or applicable for driving and setting nails or other hammering work of a similar nature. The power hammer of the present invention is specifically intended for this type of application.

Accordingly, it is an object of the present invention to provide improved power hammers. In this respect, it is a more particular object to provide improved power hammers which are particularly adapted to do the work nor mally done with conventional hammers, by using power to do the impact work quicker, better and easier.

It is another object of the present invention to provide improved power hammers having improved means for adjustably varying the impact delivered by it.

It is another object of the present invention to provide improved power hammers having a retractable nail guide.

It is still another object of the present invention to provide improved power hammers which are light in weight so as to be portable and which are rugged in construction so as to be as maintenance free as possible.

It is still another object of the present invention to provide improved power hammers which can be actuated by means of an electric motor, a solenoid, air or other similar means. In this respect, it is further contemplated that a variable speed control can be provided for the motor to vary the impact and that a rechargeable power pack can be provided to give it complete portability.

It is still another object of the present invention to provide improved power hammers which are adjustable to deliver varying impact blows, as required for different work.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The above objectives are accomplished with a power hammer which according to a preferred embodiment of the invention comprises a head piece which is adjustable so as to move only a preset distance, as required for different work. An electric motor provides the driving and actuating force for the head piece. By positionably adjusting the head piece, a fine control is provided for, for example, driving and setting a nail or the like. A retractable nail guide which holds the hammer on a nail without slipping off is also provided.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

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For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a side view partially sectionalized, for a power hammer exemplary of the present invention;

FIGURE 2 is a top view, partially sectionalized, of the power hammer of FIG. 1;

FIGURE 3 is a view illustrating the adjustable head piece of the power hammer of FIG. 1;

FIGURE 4 is an enlarged section illustrating the mechanism of the adjustable head piece;

FIGURE 5 is an exploded perspective view of the adjustable head piece;

FIGURE 6 is a partial sectional view of a driving and actuating mechanism, in accordance with a second embodiment of the invention; and

FIGURES 7 and 8 are views illustrating a second and a third construction for the adjustable head piece.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring now to the drawings, in FIGS. 1 and 2 there is shown a power hammer 10 which is generally pistolshaped having a grip 12, a trigger 14 for actuating the power hammer in the manner described below and a barrel portion 16. Mounted below the barrel portion 16 is an electric motor 18 which is electrically powered, by means of the conductor 20 extending from the grip 12. The end of the conductor 20 has a plug (not shown) for connecting the power hammer to the volt source normally found in the home or office.

Within the barrel portion 16 is a piston 22 which is driven, by means of the electric motor 18, against a hammer head shaft 24. A nail guide 26 is retained about the end of the hammer head shaft 24 and is extended beyond its end so as to provide a recessed nail head cavity 28. The head piece comprising the hammer head shaft 24 and the nail guide 26 is adjustable by means of a setting ring 30, an impact control lug carrier ring 32 and an impact control lug 34 to adjust the impact provided by the power hammer 10, in a manner described below.

More specifically, the interior of the barrel portion 16 of the power hammer 10 is step shaped and adapted to slidably retain the hammer head shaft 24 therein. The hammer head shaft 24 is also step-shaped and has an end portion 36 which engages a first step 38 of the barrel portion 16. Between a second step 40 of the barrel portion 16 and a step 42 of the hammer head shaft 24 is a spring 44 which functions to forcibly urge the hammer head shaft 24 toward the grip end of the power hammer. The outer periphery of the barrel portion 16 has a thread portion 46, for threadably receiving the variable setting ring 30 which is fixedly held in place by means of a ball and spring detent 48 retained within a cavity 50 formed in the wall of the barrel portion 16 (best seen in FIG. 4).

The impact control lug 34 is passed through an elongated aperture 52 (best seen in FIG. 2) formed in the hammer head shaft 24 and is threadably received and retained by the impact control lug carrier ring 32. The front edge of the elongated aperture 52 is normally engaged with the impact control lug 34, by the action of the spring 44. It can be seen that by rotating the setting ring 30 to thread it forward or backward on the threaded portion 46 of the barrel portion 16 the position of the carrier ring 32 and the impact control lug 34, and hence the hammer head shaft 24, can be varied to alter the spacing between the impact surface of the hammer head shaft 24 and the piston 22. In this fashion, the impact provided by the power hammer 10 can be varied, by controlling the length of the impact stroke of the piston 22. In the illustrated embodiment, the impact stroke can be adjustably varied up to approximately /2 inch.

The nail guide 26 is tubular in shape and is retained about the end of the hammer head shaft 24 by means of a pin 51 passed through an aperture 55 formed in the hammer head shaft 24 and an elongated aperture 54 in the nail guide 26. A spring 56 is retained between the end of the nail guide 26 and a step 58 formed in the hammer head shaft 24, for bracing the nail guide outwardly from the end of the hammer head shaft and to provide the nail cavity 28.

The output shaft 60 of the electric motor 18 is threadably fixed to and rotates a flywheel 62. A second flywheel 64 is positioned above the flywheel 62. A piston arm 66 is secured between the flywheels 62 and 64 by means of a pin 68 which is passed through apertures formed in each, off-center so as to provide a reciprocating action to the piston arm 66, and hence the piston 22 to which it is connected, as the flywheels 62 and 64 are rotated. A vacuum slit 70 is provided in the barrel portion 16, adjacent the end of the piston 22 to prevent a vacuum from being created within the barrel as the piston 22 is reciprocated.

A fork rest 72 having a pair of spaced apart tongs 73 and 74 is secured beneath the barrel portion 16 by means of a bracket 76. The end of the fork rest 72 opposite the tongs 73 and 74 is retained within a tubular spring retainer 78. A spring 80 within the spring retainer 78 bears against the end of the fork rest 72 and biases it outwardly away from the end of the power hammer 10.

To use the power hammer to, for example, drive and set a nail, the fork rest 72 is positioned so that the tongs 73 and 74 on its end are on opposite sides of the nail, as for example, the nail 82 shown in FIGS. 1 and 2, and the head of the nail is within the cavity 28 formed by the nail guide 26. The setting ring 30 is adjusted by rotating it, to deliver a soft or a hard impact. A series of graduations 84 and an index 86 can be advantageously provided to indicate the direction in which to rotate the setting ring 30, to deliver a softer or a harder impact blow.

The trigger 14 is operated to energize the electric motor 18. A trigger lock 88 can be provided to lock the trigger 14 in its operated position. When the electric motor 18 is energized, the flywheels 62 and 64 are rotated, and the piston arm 66 being secured to them in an eccentric position and to the piston 22, reciprocably operates the piston 22 to strike the end of the hammer head shaft 24. It can be seen that the spacing between the end of the piston 22 and the hammer head shaft 24 will determine the impact blow delivered by the hammer head shaft to the nail. If the setting ring 30 is adjusted so that the spacing is large, a soft impact will be provided since the hammer head shaft 24 will only be moved a short distance by the impact of the piston 22. Correspondingly, if the setting ring 30 is adjusted so as to provide a small spacing, a larger impact will be delivered. It will also be noted that the hammer head shaft 24 will tend to vibrate between impact blows from the piston, due to the action of the spring 44. A variable speed control for motor 18 can also be provided, if desired, to slow the speed of the motor to, in turn, adjust the provided impact.

When the end of the nail guide 26 engages the surface of the material into which the nail is being driven and set, the setting ring 30 can be continuously adjusted to provide impacts which decrease in strength so that the surface of the material will not be marred. A nail or other like object can therefore be driven and set rapidly and easily, and in a fashion such that the material is not marred or damaged. As the nail is being driven, pressure exerted on the grip of the power hammer 10 forces the end of the fork rest 72 into the spring retainer 78. The cavity 28 in the nail guide 26 assists in captivating the end of the nail so that the power hammer is easily held in contact with the nail.

A pivotal spring carrying clip 92 can be provided on the upper surface of the grip 12 and a nail extractor 94 can be provided along its lower surface. The nail extractor 94 may be extended below the electric motor 18, to provide additional support for it.

In FIG. 6 there is shown a driving and actuating mechanism for the piston 22, constructed in accordance with a second embodiment of the invention. A fiywheel 96 is fixed to a shaft 98 which is journalled in the casing of the power hammer and in a back wall 100 and has a cam surface 102 thereon. The piston 22 has a cam surface 104 formed on its end which is engaged by the cam surface 102 to cause the piston 22 to be reciprocally operated, in the manner described above. In this case, a spring 106 is provided to bias the piston 22 toward the flywheel 96, to provide the reciprocal action. It can be seen that as the flywheel 96 is rotated, its cam surface 102 strikes the cam surface 104 on the end of the piston 22 to move it forward, against the hammer head shaft 24.

The shaft 98 of FIG. 6 can be the output shaft of an electric motor or it can be merely an exposed shaft and the drill bit of an electric drill afifixed to it to provide the rotating force for the flywheel 96. With this construction, a source of power therefore need not be an integral part of the power hammer, and it can be operated by motivating means, such as an electric drill or the like.

In FIGS. 7 and 8 there are shown alternative constructions for adjustably positioning the hammer head shaft 24. In FIG. 7, a pin 110 which ma be a spring loaded two-piece pin is fixedly retained within a groove 111 formed in the setting ring 30 and is passed through an elongated aperture 112 formed in the hammer head piece 24. With this construction, the impact control lug carrier ring 32 is eliminated and the pin 110 function as the control lug, in the manner described above. That is, as the setting ring 30 is adjustably positioned, the pin 110 rides in the groove 111 and bears against the front edge of the elongated aperture 112 to position the hammer head shaft 24.

In FIG. 8, the carrier ring 32 is threadedly fixed to the setting ring 30 and is rotated along with it, rather than being merely engaged by the setting ring, as in the first described embodiment. In this case also, the control lug 34 rides within a groove formed in the carrier ring, as it is rotated. In this case also, the control lug may be a two-piece spring loaded lug.

It may be noted that unlike presently available power hammers, the hammer head shaft and the piston for operating it are two separate elements and not a single element. This feature contributes substantially to the ability of providing repeated impacts of varying strengths. Accordingly, an operable power hammer can be provided by eliminating the adjustable setting ring 30 and relying upon the action of the separate hammer head shaft and piston to provide repeated impacts.

In this respect, variable impacts can be provided in a structure of the latter type by providing a variable speed control for the motor 18. B slowing the speed down, lighter impacts can be provided. correspondingly, by speeding up the motor, stronger impacts can be provided.

The power hammer 10 can be used to hammer any item, for example, in setting and aligning studs and the like. In such a case, the nail guide 26 merely retracts to an inoperative position, or it can be eliminated.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efiiciently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Now that the invention has been described, what is claimed as new and desired to be secured by Letters Patent is:

1. A power hammer comprising, in combination: a barrel having a grip end and a nail driving end; a hammer head shaft slidably retained within said barrel and normally biased toward said grip end of said barrel; means for securing said hammer head shaft within said barrel; a piston within said grip end of said barrel adapted to engage said hammer head shaft; and means for driving said piston in a reciprocal manner to engage and drive said hammer head shaft toward said nail driving end.

2. A power hammer comprising, in combination: a barrel having a grip end and a nail driving end; a hammer head shaft slidably retained within said barrel and normally biased toward said grip end of said barrel; a piston within said barrel; a threaded portion on said barrel; a setting ring threadedly retained onsaid threaded portion of said barrel and connected to said hammer head shaft whereby as said setting ring is rotated said hammer head shaft is positionably adjusted within said barrel with respect to said piston; and means for driving said piston in a reciprocal manner to engage and drive said hammer head toward said nail driving end.

3. A power hammer comprising, in combination: a barrel; a hammer head shaft slidably retained within said barrel and normally biased toward one end of said barrel; a tubular nail guide slidably retained about the end of said hammer head shaft and normally biased to extend outwardly from the end of said hammer head shaft so as to provide a nail head cavity; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; means operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; a piston within said barrel; and means for driving said piston in a reciprocal manner to engage said hammer head shaft.

4. A power hammer comprising, in combination: a barrel; a hammer head shaft having a first and a second elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said first elongated aperture and operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said first elongated aperture against said shaft means; a piston within said barrel adapted to engage said hammer head shaft in a reciprocal manner; means for driving said piston in a reciprocal manner; a nail guide slidably retained about the end of said hammer head shaft by means of a pin extended through said second elongated aperture and retained by said nail guide; and biasing means for forcibly urging an end of said nail guide outwardly from the end of said hammer head shaft so as to provide a nail head cavity.

5. A power hammer comprising, in combinationz'a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture; shaft retaining means for retaining said shaft means within said elongated aperture, said shaft retaining means being slidably retained about said barrel and operated by said setting ring as it is rotated to move said shaft means to positionably adjust said hammer head shaft within said barrel; a piston within said barrel adapted to engage said hammer head shaft in a reciprocal manner; and means for driving said piston in a reciprocal manner.

6. A power hammer comprising, in combination: a

barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring having an annular groove formed therein threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture and engaged within said annular groove, said shaft means being operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said elongated aperture against said shaft means; a piston within said barrel; and means for driving said piston in a reciprocal manner to engage said hammer head shaft.

7. A power hammer comprising, in combination: a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft retaining means having an annular groove formed therein slidably retained about said barrel and secured to said setting ring; shaft means extending through said elongated aperture and retained within said annular groove, said shaft means being operated as said setting ring is rotated to positionably adjust said hammer head shaft within said barrel; a piston within said barrel; and means for driving said piston in a reciprocal manner to engage said hammer head shaft.

8. A power hammer comprising, in combination: a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture and operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said elongated aperture against said shaft means; a piston Within said barrel; means for driving said piston in a reciprocal manner to engage said hammer head shaft; and a fork rest fixedly secured to said barrel and adapted to be resiliently retracted and expanded.

9. A power hammer comprising, in combination: a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture and operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said elongated aperture against said shaft means; a piston within said barrel; motor means having an output shaft; fly wheel means rotated by said output shaft; a piston arm eccentrically secured to said fly Wheel means and secured to said piston, whereby said piston is driven in a reciprocal manner to engage said hammer head shaft.

10. A power hammer comprising, in combination: a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture and operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said elongated aperture against said shaft means; a piston having a cam thereon slidably retained within said barrel; a fly wheel having a cam thereon positioned within said power hammer so that said cam engages the cam on said piston as said fly wheel is rotated; a shaft for supporting and for driving said fly wheel; and means secured to said shaft for rotating said shaft, whereby said piston is driven in a reciprocal manner to engage said hammer head shaft.

11. A power hammer comprising, in combination: a barrel; a hammer head shaft having a first and a second elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft retaining means slidably retained about said barrel; shaft means extending through said first elongated aperture and retained therein by said shaft retaining means; said shaft retaining means being operated by said setting ring as it is rotated to move said shaft means to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said first elongated aperture against said shaft means; a piston within said barrel adapted to engage said hammer head shaft; means for driving said piston in a reciprocal manner; a nail guide slidably retained about the end of said hammer head shaft by means of a pin extended through said second elongated aperture and retained by said nail guide; biasing means for forcibly urging an end of said nail guide outwardly from the end of said hammer head shaft so as to provide a nail head cavity; and a fork rest fixedly secured to said barrel and adapted to be resiliently extended and retracted.

12. A power hammer comprising, in combination: a barrel; a hammer head shaft slidably retained within said barrel and normally biased toward one end of said barrel; a tubular nail guide slidably retained about the end of said hammer head shaft and normally biased to extend outwardly from the end of said hammer head shaft so as to provide a nail head cavity; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; means operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; a piston within said barrel; means for driving said piston in a reciprocal manner to engage said hammer head shaft; and a fork rest fixedly secured to said barrel and adapted to be resiliently retracted and extended.

13. A power hammer comprising, in combination: a barrel; a hammer head shaft having an elongated aperture formed therein slidably retained within said barrel; a threaded portion on said barrel; a setting ring threadedly retained on said threaded portion of said barrel; shaft means extending through said elongated aperture and operated by said setting ring as it is rotated to positionably adjust said hammer head shaft within said barrel; biasing means for forcibly urging an end of said elongated aperture against said shaft means; a piston within said barrel adapted to engage said hammer head shaft in a reciprocal manner; and means for driving said piston in a reciprocal manner.

References Cited UNITED STATES PATENTS 1,470,645 10/1923 Roberts 173-1 15 2,220,195 11/ 1940 Amundsen 173-115 2,315,993 4/1943 Weyandt et al. 2,657,383 1l/1953 Siering et al. 2,942,852 6/1960 Muthmann 173-123 XR GRANVILLE Y. CUSTER, JR., Primary Examiner. 

